Aizen Sosuke is the former captain of the Fifth Division of the Gotei 13, one of the main antagonists in the history of the worlds. For over a hundred years he hid behind the mask of a benevolent and modest officer, secretly conducting inhumane experiments and preparing betrayal. His goal is to overthrow the Soul King and take the place of god, standing above all worlds. Aizen possesses colossal spiritual power, unsurpassed intellect, and the ability to fully hypnotize through his spiritual sword Kyoka Suigetsu. After the conspiracy was exposed, he fled to Hueco Mundo, where he created an army of Arrancars and began a war against the Soul Society. Having been defeated by Kurosaki Ichigo and Urahara Kisuke, he was imprisoned in Muken for 20,000 years. During the Thousand-Year Blood War with the Quincies, he was temporarily released to be used against Yhwach, and Aizen played a key role in the final battle, once again using his illusions. After the victory, he was sealed again.